Adjustable receiver port construction for jet pipe servovalve

ABSTRACT

Disclosed is a jet pipe type servovalve wherein the feed tube is disposed angularly with respect to a flapper to which it is affixed and which is movable by a torque motor the armature of which is connected to the flapper. The feed tube has one end thereof affixed rigidly to the housing and the other end thereof terminating in a nozzle which is directed toward a receiver. The output ports of the receiver are connected to the end chambers of a cylinder within which a power control valve is slidably positioned so as to control the flow of fluid under pressure from a source thereof to an apparatus to be positioned such as an actuator. The receiver ports are adjustable laterally and rotationally with respect to the jet pipe nozzle.

United States Patent Inventors Clyde E. Cobb;

Charles E. Jones, both of Lake View Terrace, Calif.

Appl. No. 833,033

Filed June 13, 1969 Patented June 15, 1971 Assignee Bell Aerospace Corporation ADJUSTABLE RECEIVER PORT CONSTRUCTION FOR JET PIPE SERVOVALVE 1 Claim, 2 Drawing Figs.

U.S. Cl 137/83, l37/625.64, 137/625.63 Int. Cl F1511 5/00, 005d 16/00 Field of Search 137/83,

[56] References Cited UNlTED STATES PATENTS 3.324,871 6/1967 Farnan 137/83 Primary Examiner-Alan Cohan Attorney-Nilsson, Robbins. Wills & Berliner ABSTRACT: Disclosed is a jet pipe type servovalve wherein the feed tube is disposed angularly with respect to a flapper to which it is affixed and which is movable by a torque motor the armature of which is connected to the flapper. The feed tube has one end thereof affixed rigidly to the housing and the other end thereof terminating in a nozzle which is directed toward a receiver. The output ports of the receiver are connected to the end chambers of a cylinder within which a power control valve is slidably positioned so as to control the flow of fluid under pressure from a source thereof to an apparatus to be positioned such as an actuator. The receiver ports are adjustable laterally and rotationally with respect to the jet pipe nozzle.

ADJUSTABLE RECEIVER PORT CONSTRUCTION FOR JET PIPE SERVOVALVE BACKGROUND OF THE INVENTION Jet pipe servovalves have long been known and typical examples of such apparatus are shown in U.S. Pat Nos. 2,884,906; 2,884,907; 2,996,072 and 3,017,864. As can be seen from these prior art patents, typical jet pipe servovalves are constructed in such a manner that the feed tube and the armature of the torque motor are an integral unit or at the most the feed tube is axially an extension of the torque motor armature. As a result the degree of movement of the nozzle tip, which terminates the feed tube, is limited by the amount of movement of the armature in the torque motor. Furthermore, alignment between the jet pipe nozzle orifice and the receiver ports is somewhat difficult to obtain and there is little or no adjustment available.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram shown in perspective of a jet pipe servovalve constructed in accordance with the present invention;

FIG. 2 is a cross-sectional view of the receiver port portion of the servovalve illustrated in FIG. 1, taken about the line 2-2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 where is illustrated a jet pipe servovalve which includes a torque motor llhaving pole pieces 12 and 13 with an armature 14 disposed therebetween. A pair of coils l and 16 are disposed to receive an input signal upon leads 17 thereby to provide movement of the armature, as in dicated by the arrow 18, which is proportional to the magnitude of the input signal.

A flapper 21 is rigidly connected to the armature 14 so as to move it as indicated by the arrow 20 in response to movement of the armature 14. The flapper 21 is suspended within a torque tube 22 so as to provide a seal between the fluid sections of the servovalve and the torque motor. Such a suspension is well known and, for example, is illustrated in U.S. Pat. No. 3,221,760. A feed tube 23 has one end thereof rigidly affixed to a retainer member 24 which in turn is rigidly affixed to the body portion 25 of the housing. The feed tube 23 is constructed of a hollow flexure tube which is movable with respect to the housing. Movement is imparted to the tube 23 by way of a flexible connection such as the link or spring clip 26 which is rigidly affixed to the flapper 21, but is releasably attached to the tube 23 by being inserted through an opening 27 defined by the clip 26. Thus, as the flapper 21 moves the feed tube 23 also is caused to move as indicated by the arrow 28. As is illustrated by the difference in arrows 20 and 28, the mechanical interconnection provides amplification of movement of the nozzle tip as compared to the flapper 21. Thus, small armature movement results in larger nozzle tip movement. The feed tube terminates in an ejector end having a nozzle 29 which is directed toward ports 31 in a receiver means 32.

Fluid under pressure is provided from a source thereof (not shown) through conduits 33 and 34 to the fixed or receiving end portion of the feed tube 23. As the nozzle 29 moves with respect to the receiver ports 31, differential pressure is applied through conduits 35 and 36 to the end chambers 37 and 38, respectively, of the power control valve spool shown generally at 40. The structure of a flow control valve spool is well known in the prior art and, for example, detailed description thereof may be found in the above referenced patents or U.S. Pat No. 2,947,286. Generally movement of the valve spool 41 in response to differential pressure thereacross in the end chambers 37 and 38 as indicated by the arrow 42, causes fluid under pressure to flow through the conduits 33, and 43 or 44 to an actuator connected to cylinder ports 45 and 46 de endmg upon the direction of movement of the valve 41. s the valve 41 thusly moves, such movement is transmitted by way ofa feedback spring 47 which is affixed to the armature 14.

As is illustrated in FIG. 2 to which reference is hereby made, the body section 25 on the valve defines a bore 51 in which the receiver means 32 is disposed as is illustrated. TI'Ie receiver means 32 is constructed of a cylindrical plug 52 having a pair of increased diameter sections or lands 53 and 54 thereon. The outer diameter of the lands 53 and 54 is substantially the same as the diameter of the bore 51 so that an interference fit is accomplished between the lands and the bore 51 to thereby hold the receiver means 32 in position. A counter bore 55 and 56 is provided at each end of the bore 51. Plugs such as the well-known Lee plugs 57 and 58 are inserted into the counter bores 55 and 56, respectively, to seal each end of the bore 51 subsequent to positioning of the receiver port means 32, as is illustrated. Once the plugs 57 and 58 are in position a chamber 61 is provided between the plug 57 and one end of the receiver means 32 while another chamber 62 is provided between the opposite end of the receiver 32 and the plug 58. The cylindrical plug is drilled from opposite ends to provide openings 63 and 64 which communicate with the chamber 62 and 61, respectively. Additional bores are provided by way of the receiver ports 31 and 30 which are separated by a central web 65. When the feed tube is in position with the nozzle 29 disposed directed toward the receiver ports 30, 31 as illustrated, the receiver ports must be positioned accurately to provide proper operation of the jet pipe servovalve.

To accomplish the required adjustment of the receiver bores 30 and 31 with respect to the nozzle 29 the cylindrical plug 52 is press-fitted into the bore 51 and moved laterally along the longitudinal axis 66 of the bore until fluid flow through the receiver ports 30 and 31 is balanced in the chambers 61 and 62. The cylindrical plug is then rotated within the bore 51 until the pressure in the chamber 61 and 62 is at a maximum, Under these conditions, the receiver ports 30 and 31 are properly positioned with respect to the fluid flow from the nozzle 29, assuming no input signal to the torque motor.

We claim:

1. A jet pipe servovalve comprising:

a housing having a body portion defining a bore;

a feed tube mainted within said housing and having one end terminating in a nozzle; and

receiver means including a cylindrical plug having a plurality of lands thereon positioned within said bore, said cylindrical plug being movable longitudinally along said bore and being rotatable within said bore for aligning said receiver means with respect to said nozzle, said lands effecting an interference fit with said bore, said interference fit being the only means for retaining said receiver means aligned with respect to said nozzle. 

1. A jet pipe servovalve comprising: a housing having a body portion defining a bore; a feed tube mainted within said housing and having one end terminating in a nozzle; and receiver means including a cylindrical plug having a plurality of lands thereon positioned within said bore, said cylindrical plug being movable longitudinally along said bore and being rotatable within said bore for aligning said receiver means with respect to said nozzle, said lands effecting an interference fit with said bore, said interference fit being the only means for retaining said receiver means aligned with respect to said nozzle. 